The candidate's career goal is to become an independent research investigator and make major contributions to advance science in order to improve human health. The candidate is particularly interested in using chemical probes to understand how environmental toxins affect human health through targeting EET and related lipid-mediators signaling pathways. He has had excellent training in chemical biology, protein chemistry, and molecular biology throughout his career. He has applied his knowledge of using chemical probes to study biological effects to several key systems, including that of cytochrome P450, rhodopsin, and soluble epoxide hydrolase (sEH). He now plans to further complement his training by learning to conduct specialized cell-based assays, advanced proteomics, to operate state-of-the-art accelerator mass spectrometer (AMS), and to analyze AMS data in order to identify the receptor(s) of EETs for the first time. During the K99 phase, he will attend courses and seminars, and will present at national meetings in order to improve his technical writing, presentation, teaching, and leadership skills. By the end of the award, he will have publication records and more than enough preliminary data to apply for R21 and R01 grants through the NIH. During the K99 phase, the candidate will be trained under the supervision of Dr. Bruce Hammock at the University of California, Davis. Dr. Hammock is an elected member of National Academy of Science who studies how environmental exposures affect human health. His research focuses on the xenobiotic enzyme called sEH, a major enzyme that degrades epoxy fatty acids. Dr. Hammock is the pioneer of using a multidisciplinary approach to characterize sEH and to study its role in human diseases like hypertension, inflammation, cancer, fibrosis, and neuropathic pain. Through inhibition of sEH, Dr. Hammock has shown that epoxy fatty acids from ?-6 dietary and ?-3 dietary acids play a vital role in several biological processes such as cardiovascular functioning and inflammation response. In addition, the candidate will learn to run specialized cell-based assays related to the cardiovascular system under co-mentor Dr. Chiamvimonvat who is an expert in cardiovascular disease. He will also learn advance proteomics from Dr. Gomes who also has an excellent track record in this field. Lastly, he will learn to operate AMS and to analyze AMS data under the supervision of Dr. Bruce Buchholz, an expert in AMS. UC Davis is one of the top institutions in the world for biological research. Its programs in environmental science and biological science are internationally acclaimed, ranking twelfth and twenty-fifth in the world, respectively. The institution hosts 800 faculty members who are specialized in biological sciences or biomedical research. The departments at UC Davis organize seminars, lectures, workshops, and discussion sessions on a daily basis, which will allow the candidate to interact with experts in different areas. UC Davis also has many core facilities that house a number of state-of-the-art instruments. These instruments are made easily accessible to scientists at UC Davis and training is always provided. Thus, the candidate can both expand the breadth of his academic knowledge and also learn to use specialized instruments that will help his research. The goal of this proposed project is to identify the receptor(s) of epoxy-eicosanoids, which are lipid signaling molecules. Epoxy-eicosanoids, also known as epoxyeicosatrienoic acids (EETs), are potent chemical mediators that play important roles in inflammation, vasoregulation, analgesia, and angiogenesis. The in vivo levels of EETs are greatly affected by exposure to environmental toxins, such as triclocarban (TCC), 2, 3, 7, 8- tetrachloro-dibenzodioxin (TCDD), and peroxisome proliferators. The changes in in vivo levels of EETs lead to physiological changes that could affect human health. The long-term goal for this project is to understand how the modulation of EET and related lipid mediators signaling pathways affect human health. Although there have been decades of research on this subject, the molecular mechanism of how EETs initiate the signal transduction cascade remains unknown. In the proposed research, the candidate will test the hypothesis that EETs induce the signaling pathway through binding to specific cell-surface receptor(s). The ultimate goal of this proposal is to identify the receptors of EETs for the first time. To identify the receptor(s) of EETs, which are both lipophilic and labile, the intent is to use a combination of C-14 (14C) mass label, photo labels and AMS. AMS, which counts 14C atoms directly, is 100K times more sensitive than any of the traditional decay counting method. This dramatically increases sensitivity has several advantages that will strongly enhance this chances of identifying the EET receptors. The candidate hypothesizes that using AMS with the use of 14C ligands coupled with unique photo labels represents a new method to identify very low-abundance receptors with highly lipophilic and liable ligands. This project, when accomplished, will have a huge impact on basic science and public health. 1) Identification of the receptor(s) of EETs will allow us to bettr understanding the signaling pathway of EETs. 2) The identified EET receptor(s) will provide a way to screen for the environmental toxins that target EET pathway. 3) The method for receptor identification developed in this proposal will become a new method for general receptor identification.